Could you tell us what you've already tried? Note that there's no FileZilla server for Ubuntu, but of course there are plenty of others which all are pretty well documented (proftpd for example).
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slhck♦Feb 1 '13 at 15:13

I've submitted an edit for this title, as he wants users to be able to use the FileZilla client, so the title is misleading. I do suggest a google search for this, or even some apress books on ubuntu server administration. even openssh comes w/ sftp which works fine.
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BigHomieFeb 1 '13 at 16:07